The answer to this question depends on what YOU want the shed to do?
Both the American Barn and the Aussie Barn have a centre section and two annexes or wings. The idea behind the American style barn is that you can have a high centre section with which you can either install a tall opening roller door or perhaps a mezzanine floor area.
Often an American barn design is used for stables or stable complexes with the centre section forming a breezeway and also giving the extra height needed for a decent sized horse float or horse transport truck.
Aussie Barn sheds remind me of the classic old Australian colonial farm building and in the past I have seen them used as weekenders, farm sheds, tourist centres and also for stables or stable complexes.
Many of the good reputable steel shed suppliers can offer sliding door options on barns rather than roller doors and offer stable doors and stable panels as well. The added centre height that is available with an American Barn Shed makes it ideal for the addition of a Mezzanine floor. The mezzanine floor area is often used for studio or temporary accommodation or for additional storage area.
Many Barns have a steep pitch to the centre section. If you need extra height in your barn then make sure you ask for a steep pitch to your centre section. Usually the wings or Annexes are at a 10 degree pitch.
Another important aspect when contemplating an American or Aussie Barn are the internal columns. These can be handy if you need places to fix the internal stable panels or perhaps walls to living or office areas. If you need open clear spanning areas then consider a traditional gable end shed.
When planning your shed dont forget to consider insulation, vermin proofing etc.